Biodegradable polyester resin composition, biodegradable polyester film including the same and biodegradable molded article including biodegradable polyester resin composition

1. A biodegradable polyester resin composition, comprising: a polyester resin comprising a diol, an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid,

wherein an alternating ratio of the polyester resin ranges from 0.37 to 0.59,

wherein the alternating ratio is a first ratio of a first diol quantity, bonded between the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid, to a total quantity of the diol in the polyester resin,

wherein the diol comprises 1,4-butanediol, the aromatic dicarboxylic acid comprises terephthalic acid or dimethyl terephthalate, and the aliphatic dicarboxylic acid comprises adipic acid,

wherein the number average molecular weight of the polyester resin is about 40000 g/mol to about 90000 g/mol,

wherein a tensile strength measured by the measurement method below ranges from 40 MPa to 60 MPa:

wherein, in the measurement method, the biodegradable polyester resin composition is dried at 80° C., placed in a stainless steel mold, and compressed at 210° C. under a pressure of 10 MPa for 3 minutes to produce a polyester sheet having a thickness of 300 μm, and a tensile strength of the polyester sheet is measured,

wherein an elongation at break of the polyester sheet ranges from 800% to 1100%,

wherein a Young's modulus of the polyester sheet ranges from 20 MPa to 80 MPa,

wherein the biodegradable polyester resin composition comprises an oligomer in a content ranging from about 3000 ppm to about 30000 ppm based on the total amount of the biodegradable polyester resin composition,

wherein the molecular weight of the oligomer ranges from about 400 to about 1300, and

wherein the oligomer comprises a reaction product of 1,4-butanediol, terephthalic acid and adipic acid.

2. The biodegradable polyester resin composition according to claim 1 , wherein the alternating ratio ranges from 0.4 to 0.56.

3. The biodegradable polyester resin composition according to claim 1 , wherein the alternating ratio ranges from 0.45 to 0.53.

4. The biodegradable polyester resin composition according to claim 1 , wherein a hard segment ratio of the biodegradable polyester resin composition ranges from about 0.2 to about 0.3,

wherein the hard segment ratio is a second ratio of a second diol quantity, bonded between the aromatic dicarboxylic acid, to the total quantity of the diol in the polyester resin.

5. The biodegradable polyester resin composition according to claim 4 , wherein a soft segment ratio of the biodegradable polyester resin composition is about 0.21 to about 0.31,

wherein the soft segment ratio is a third ratio of a third diol quantity, bonded between the aliphatic dicarboxylic acid, to the total quantity of the diol in the polyester resin.

6. The biodegradable polyester resin composition according to claim 5 , wherein the soft segment ratio is larger than the hard segment ratio.

7. The biodegradable polyester resin composition according to claim 1 , wherein a biodegradability after nine weeks of the biodegradable polyester resin composition is 85% or more,

wherein the biodegradability after nine weeks is measured by the measurement method below:

in the measurement method, the biodegradability after nine weeks is a molecular weight reduction rate compared to an initial molecular weight of the biodegradable polyester resin composition when the biodegradable polyester resin composition is placed at a temperature of 60° C. and a humidity of 90% for 9 weeks under a composting condition.

8. A biodegradable polyester resin composition, comprising: a polyester resin comprising a diol, an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid,

wherein a hard segment ratio of the polyester resin ranges from 0.2 to 0.3,

wherein the hard segment ratio is a ratio of a diol quantity, bonded between the aromatic dicarboxylic acid and the aromatic dicarboxylic acid, to a total quantity of the diols diol in the polyester resin,

wherein the diol comprises 1,4-butanediol, the aromatic dicarboxylic acid comprises terephthalic acid or dimethyl terephthalate, and the aliphatic dicarboxylic acid comprises adipic acid, wherein the number average molecular weight of the polyester resin is about 40000 g/mol to about 90000 g/mol,

wherein a tensile strength measured by the measurement method below ranges from 40 MPa to 60 MPa:

wherein, in the measurement method, the biodegradable polyester resin composition is dried at 80° C., placed in a stainless steel mold, and compressed at 210° C. under a pressure of 10 MPa for 3 minutes to produce a polyester sheet having a thickness of 300 μm, and a tensile strength of the polyester sheet is measured,

wherein an elongation at break of the polyester sheet ranges from 800% to 1100%,

wherein a Young's modulus of the polyester sheet ranges from 20 MPa to 80 MPa,

wherein the biodegradable polyester resin composition comprises an oligomer in a content ranging from about 3000 ppm to about 30000 ppm based on the total amount of the biodegradable polyester resin composition,

wherein the molecular weight of the oligomer ranges from about 400 to about 1300, and

wherein the oligomer comprises a reaction product of 1,4-butanediol, terephthalic acid and adipic acid.

9. The biodegradable polyester resin composition according to claim 8 , wherein the hard segment ratio ranges from 0.21 to 0.28.

10. The biodegradable polyester resin composition according to claim 8 , wherein the hard segment ratio ranges from 0.22 to 0.27.

11. A biodegradable molded article, comprising the biodegradable polyester resin composition of claim 1 .

12. A biodegradable molded article, comprising the biodegradable polyester resin composition of claim 8 .